Primates utilize several visual cues to provide information about depth. To understand how these cues are processed, it is essential to know how, at perceptual level, simultaneously presented depth cues are integrated; and how, at single neuron level, these depth cues are jointly processed. In the proposed work I plan to systematically study the interaction among three depth cues, stereopsis, motion parallax and shading. The purpose of the proposed experiments is to examine the ability of rhesus monkeys to co-process different depth cues and to then determine how this is accomplished in the visual system. The research will be carried out in three stages. In the first the visual capacities of monkeys will be behaviorally assessed for co-processing depth information based on stereopsis, motion parallax and shading. In the second single cell recordings will be made to examine how these cues are co-processed by neurons in areas V1, V2, V4, and MT. There is increasing evidence to the effect that single cells in cortex are multifunctional and are thus capable of extracting several features from the visual scene. By examining the neuronal co-processing abilities in various cortical areas, it will be possible to determine at what level such information is integrated. In the third phase of the research the role various neurotransmitters play in depth analysis will be assessed by making local injections of glutamate and GABA agonists and antagonists. [unreadable] [unreadable] [unreadable]